These are some of the UK's most notorious murderers whose cases and legal appeals have triggered Home Secretary David Blunkett's decision to issue new sentencing principles for the courts.

Name:

Myra Hindley

Crime:

With Ian Brady, murdered four children during 1963 and 1964 and buried their bodies on Saddleworth Moor, near Manchester in northern England. The four were Lesley Ann Downey, 10, Keith Bennett, 12, Edward Evans, 17, and Pauline Reade, 16. The pair also murdered John Kilbride, 12.

Jailed for life in May 1966, Hindley - unlike Brady - pursued a long campaign for parole up to her death in November 2002, at the age of 60. In 1998, Appeal Court judges upheld then Home Secretary Jack Straw's decision that Hindley should stay in prison until she died, unless there were "exceptional circumstances" to review the tariff. Her case was also rejected by five law lords in 2000, when they ruled unanimously that Mr Straw's decision had been lawful and justified. Both rulings came before the Human Rights Act was passed into UK law.

Name:

Anthony Anderson

Crime:

Killed two men - Thomas Walker, 60, and Michael Tierney, 35 - in separate attacks after being let into their homes. Mr Walker, 60, was in "obvious" poor health and after being punched and kicked by Anderson in September 1986, suffered a heart attack and died. Mr Tierney, 35, similarly died from injuries in May 1987 after being kicked by Anderson. In both cases he also stole property from his victims.

Anderson was convicted in 1988 of two murders and given two life sentences. The judge, with the agreement of the lord chief justice, set a tariff of 15 years. In July 1994, then home secretary Michael Howard increased Anderson's minimum term to 20 years, and that was confirmed by Mr Howard's successor Jack Straw. He said the tariff was justified because Anderson - now aged 40 - had killed on two separate occasions. A legal challenge to the home secretary's decision (launched jointly with John Taylor - see below) was rejected in 2001 by the court of appeal, which confirmed the home secretary's power to fix the mandatory life sentence tariffs. But Anderson's case triggered a Law Lords ruling last November that criticised the home secretary's role in setting tariffs and led to the new sentencing rules.

Name:

Robert Thompson and Jon Venables

Crime:

Aged 10, they tortured and murdered two-year-old James Bulger after abducting him from a Merseyside shopping centre in February 1993.

Convicted in November 1993 with an eight year minimum sentence, which was later raised to 10 by the then lord chief justice, and raised again to 15 years by then Home Secretary Michael Howard in July 1994. That tariff was quashed by the House of Lords after judicial review proceedings in 1997. The pair then took their case to the European Court of Human Rights and in December 1999 it ruled that judges, rather than the home secretary, should determine jail terms for juvenile killers. Lord Chief Justice Lord Woolf ruled less than a year later that the boys were eligible for immediate parole and in June 2001 they were freed, aged 18.

Name:

John Taylor

Crime:

Murdered Susan McNamara, 32, a snooker club owner, by breaking her neck then strangling her.

Sentenced to life in prison at Sheffield crown court in January 1989, the trial judge and lord chief justice set the tariff for Taylor - now aged 47 - at 16 years. In March 2001 Jack Straw, then home secretary, increased that by six years. Mr Straw gave as his reasons evidence of sexual interference with - or theft from - the victim, the absence of mitigating factors, the "brutal nature" of the attack, the absence of any particular motive, and Taylor's previous convictions. A legal challenge to the home secretary's decision (launched jointly with Anthony Anderson - see above) was rejected in 2001 by the court of appeal, which confirmed the home secretary's power to fix mandatory life sentence tariffs.

Name:

Dennis Stafford

Crime:

With Michael Luvaglio, convicted of shooting dead fruit machine cash collector Angus Sibbett, whose body was found in his Jaguar car under a bridge in County Durham in January 1967. The murder was said to have inspired the Michael Caine film Get Carter. Stafford has always insisted he is innocent.

Jailed for life in 1967 and released on licence 12 years later, Stafford breached the licence by moving to South Africa, where he became a successful businessman. On a return trip to the UK in 1989 he was arrested and returned to prison, before again being released on licence in 1991. In July 1994, Stafford was convicted of involvement in a forged travellers' cheques operation. He was sent to prison for six years, and had his release licence revoked.
After serving his tariff of three years, the Parole Board recommended in 1997 that he should be released but successive home secretaries disagreed because they thought he could commit non-violent crimes. He was eventually released on licence again, but took his case to the European Court of Human Rights, which ruled in his favour last year.